1-2% alkaline earth hydroxide modification of wool at 120-150 f. for under 15 minutes



United States Patent .12 ALKALINE EARTH HYDROXIDE MODIFICA- TION OF WOOLAT 120-150 F. FOR UNDER 15 MINUTES Arthur J. I. Harding, 41 OverdaleAve., Branting Hill,

Glenfield, Leicester, England No Drawing. Continuation-impart ofapplication Ser. No. 219,730, Aug. 27, 1962. This application May 28,1965, Ser. No. 459,876

Int. Cl. D06m 3/04 US. Cl. 8128 Claims ABSTRACT OF THE DISCLOSURE Woolis heated at 120150 F. for less than minutes in an aqueous dispersion of0.1-2 percent calcium hydroxide, washed and acidified to render it morereceptive to dyestuffs without adversely affecting the physicalproperties of the wool.

This invention relates to the treatment of wool, more particularly tothe treatment of wool to increase its afiinity to hydrophylic dyestuffsand to dyeing processes comprising such treatment. This application is acontinuationin-part of application Ser. No. 219,730, filed Aug. 27,1962.

The wool fiber is relatively resistant to dyeing with the complex, e.g., premetallized, and the hydrophylic dyestuffs, i.e., those containingone or more highly polar groups, e.g., sulfonic acid groups. Theepicuticle appears to act as a barrier to such dyestufiis. Also,retarding agents used to obtain more level dyeings or novel multicolordyeings, such as the formaldehyde-naphthalene sulfonic acid condensationproducts, increase the natural resistance of the wool fiber to dyeingwith such dyestuffs. The result is poor dyestutf exhaustions, even withprolonged high temperature dyeings which are damaging to the fibers.

It is known that treatments which damage or remove the epicuticle of thewool, e.g., chlorination and treatment with strong alkali, renders thewool fiber more receptive to hydrophylic and/or complex dyestulfs.However, for the most part, the dyeing trade prefers to use hydrophobicdyestuffs or dyestuffs of relatively low hydrophylicity or accept thelong dyeing times and poor dyestulf exhaustions associated With the useof highly hydrophylic dyestuffs rather than accept the loss of strength,elongation, and hand and increased expense associated with thesedamaging pre-treatrnents. Also, some such pre-treatments, such as drychlorination, require equipment not possessed by many dyers whichnecessitates obtaining the treated Wool from special sources atconsiderably added trouble and expense. Also, other treatments requirespecial knowledge and experience to achieve commercially acceptableresults.

The present invention is a non-damaging inexpensive, low temperatureaqueous treatment of Wool which increases the affinity of the Wool fiberto hydrophylic and complex dyestuffs and which can readily be performedby any dyer using conventional dyeing equipment.

According to this invention, wool is heated in the pres ence of auniform aqueous dispersion of an alkaline earth hydroxide underconditions which are substantially nondamaging to the wool at theselected alkaline pH in the absence of the alkaline earth hydroxide.

It is known the treatment of wool under alkaline conditions can increaseits afiinity for hydrophylic dyestuffs due to damage to the Wool fiber,e.g., by scale removal. See Kienle et al., American Dyestufi Reporter,Jan. 29, 1945; Noble, ibid., Sept. 10, 1945, p. 359; Speakman et al.,J.S.D.C., December 1938. Because of the highly adverse etfect upon hand,tensile and elongation associated with an alkaline treatment of woolwhich significantly improves its dyeability with hydrophylic dyestuffs,such alkaline treatments are not generally practiced.

If the alkaline treatment is performed under milder conditions, which donot substantially adversely affect the properties of the wool fiber,e.g., those employed in conventional degreasing treatments of raw woolstock, the increased dyestulf receptivity is marginal at most.Therefore, a non-damaging alkaline wool treatment which significantlyimproves dyestuff receptivity is not known.

It is now possible to achieve the spectacularly increased dyestuifreceptivity heretofore associated with a damaging alkaline treatment ofwool under conditions which do not materially adversely affect theproperties of the Wool fiber.

A non-damaging alkali treatment of wool which materially increases thedyestulf aflinity of the wool fiber can be achieved by treating the woolwith a uniform aqueous dispersion of an alkaline earth hydroxide at a pHabove 9.5, preferably above 10.5 e.g., from 11 to 12, but ordinarilybelow about 13, under relatively mild conditions of time andtemperature.

The fact no substantial damage has taken place as a result of treatmentcan be determined by a microscopic examination of the fibers, which willshow the scale structure is retained in a substantially undamagedcondition, and by tests for dry tensile and elongation, which propertiesshould not be significantly lowered, i.e., at least percent of theproperties of corresponding untreated wool. Further indirect proof thatno significant damage has taken place can be found in the fact that thewool, if undamaged, behaves substantially the same as normal Wool, e.g.,in felting shrinkage tests.

The treating compounds of the process of this invention are alkalineearth hydroxides, e.g., the hydroxides of the Group II-A elements of anatomic number from 12 to 56, preferably calcium hydroxide, bariumhydroxide and magnesium hydroxide, in that order of preference. Thehydroxide can be used as such or formed in situ by the use of a salt ofa Group IIA element which at least partially decomposes at a pH above9.5 to form the alkaline earth hydroxide in situ. For example, the woolcan be wet out with the solution of the selected salt and the pHgradually raised at the selected treatment temperature.

Because of the limited water solubility of the alkaline earthhydroxides, it is important the aqueous dispersion of the hydroxide isuniform. Uneven distribution of the alkaline earth hydroxide throughoutthe wool being treated results in non-uniform increased receptivity tohydrophylic dyestuffs, which will tend to result in uneven dyeings.Therefore, when using the hydroxide dispersed in an aqueous liquor,vigorous agitation of the wool and/or rapid bath circulation areimportant. Also, hydroxides of fine particle size should be employed.

The amount of hydroxide used is not critical over a wide range.Generally a 0.1 to 2 percent aqueous dispersion is used, i.e., about 5to 500 percent, calculated on the weight of the wool. Because residualalkaline earth ions tend to affect the shade of the subsequent dyeingand can produce spotting, a one percent or less dispersion is ordinarilyemployed, e.g., 0.2 to one percent, to facilitate subsequent removal.For the same reason thorough after rinsing, preferably with a final acidrinse, is important. The term dispersion also includes solutions, to theextent they can be formed, e.g., by solubilizing with sucrose.

An elevated temperature is ordinarily required to significantly modifythe dyeing properties of the wool. As a general rule, a temperature ofat least F. is required, with the preferred range being about to F.,depending upon treatment time and pH. When short reaction times areemployed, e.g., a few seconds to 5 minutes, somewhat higher temperaturesare sometimes required.

With finer grades of wool, e.g., 64s qualit or better, about 120 F. to140 F. is the preferred temperature range. With the coarser grade wools,e.g., 56s or less, a somewhat higher range, e.g., about 130 to 150 F.,is preferred. Ordinarily, a temperature below about 180 F., andpreferably below 160 F., should be used to avoid fiber damage.

A means for determining the maximum time which can be employed at theselected reaction temperature is to treat samples of wool for variousperiods of time, in the absence of the alkaline earth hydroxide, at thepH at which the treatment is to be performed and then by appropriatetests to determine the time at that pH when significant loss ofproperties begins. The optimum reaction time will be somewhat less thanthe time at that temperature and pH when such damage begins. A watersoluble base, e.g., sodium hydroxide, can be used to provide therequisite pH for the test.

The minimum time required to substantially increase the affinity of thewool fiber to hydrophylic dyestuffs is, within the pH range of 9.5 and13, determined primarily by reaction temperature. If the pH of thetreatment bath is that provided by the alkaline earth hydroxide, at 120F., usually a treatment time of at least 7 minutes is required; at 140F., at least 4 minutes; and at 160 F., at least one minute. If the pH isto be higher than that provided by the alkaline earth hydroxide, e.g.,by adjusting it upward with sodium or potassium hydroxide,correspondingly shorter reaction times will be necessary. At a pH from9.5 to 13, preferably at the pH provided by the alkaline earthhydroxide, and at a temperature within the preferred range of 120 to 150F., preferably 130 to 140 F., a treatment time between 2 and 15 minutesordinarily is employed, preferably less than 10 minutes, e.g., 5 tominutes, to ensure no substantial damage to the fiber.

Unless shorter reaction times or lower reaction temperatures aredesired, the preferred pH is that provided by the alkaline earthhydroxide. However, any pH above 9.5, but preferably below 13, isoperable and can be obtained with added alkali-metal hydroxide or basicsalt thereof, e.g., NaS, Na PO Na CO NaBO Preferably, a pH from 10.5 to12 is employed.

The wool can be treated in raw stock, top, roving yarn, fabric, clothand carpet form. Advantageously, the treatment can be incorporated intothe alkaline scour of raw wool stock conventionally used to remove thewool oils. Highly desirable results are obtained with top as thealkaline earth hydroxide can readily be uniformly distributed throughoutand then washed out of the top.

A convenient means of treating the wool involves adding the wool fibersin stock or top form to an aqueous solution or dispersion of theselected alkaline earth compound at the desired temperature, maintainingthe wool in the solution for the selected time with sufiicient agitationand/or liquor flow to insure uniform distribution of the liquor amongstthe fibers and uniform dispersion of the alkaline earth compound,removing the treating liquor, and then promptly thereafter cooling,washing, and acid scouring the fibers to insure the reaction isterminated and substantially all the alkaline earth compound is removed.The fibers can then be dried by conventional means and, if desired,tinted with a fugitive tint for identification purposes, and treatedwith lubricating oils and anti-static agents so as to be in propercondition for future processing.

Another convenient method involves applying the alkaline earth hydroxideto the top, yarn, fabric or cloth as a viscous uniform aqueousdispersion, e.g., calcium hydroxide and British gum paste, usingconventional techniques, e.g., with a Vigoureux machine, followed bydrying so that the fibers are heated to 140460 F. for several minutes.This is a useful technique for treating carpet to obtain multicoloreddyeings as described below. The dispersion can be applied uniformly oras a .4 random or predetermined pattern, if novel dyeing effects aredesired.

Using wool pretreated with alkaline earth hydroxide in the mannerdescribed herein, it is possible at the same dyeing temperature toobtain higher and usually complete dyestuff exhaustions of hydrophylicand complex dyestuffs which normally do not exhaust or do so with greatdifficulty. This means darker shades can be obtained and/ or less fiberdamage because of shorter dyeing times. Solid shades can be obtainedwith polysulfonic acid dyestuffs which heretofore could not be used onwool because they produced a skittery, non-solid shade. With hydrophylicdyestuffs which normally exhausted well at the boil, it is now possibleto achieve complete exhaustion at temperatures well below the boil,e.g., 180 F. or lower, which means less fiber damage. Whole new classesof dyestuffs which heretofore could not generally be used with wool,especially the polysulfonic acid dyestuffs, now can be used to produceexcellent dyeings on wool.

The alkaline earth hydroxide treatment can be incorporated into thedyeing process and made an integral part thereof by adding the wool toan aqueous dispersion of the alkaline earth hydroxide, bringing the bathto treatment temperature for the selected time, rinsing thoroughly withwater below the treatment temperature, bringing to a mildly acid pH withthe acid used for the dyeing and then dyeing in the conventional manner,usually with appropriate shortening of dyeing time and/ or lowering ofdyeing temperature.

With the wool treatment process of this invention, it is also possibleto achieve sharply contrasting novel multicolor and color and white dyedeffects on wool in yarn, either before or after forming into fabric andpiece form, in a single dyebath by dyeing wool yarns consistingessentially of a mixture of normal wool, i.e., wool not chemicallymodified to alter its dye receptivity, and wool pretreated with analkaline earth hydroxide as described herein, in a single dyebathcontaining a watersoluble condensation product, a suitable acid and apolysulfonic acid dyestuff and preferably also a dyestuff containingless than a total of 2 sulfonic acid and reactive groups, all as definedhereinafter.

To obtain the novel dyeing effects, the treated wool is blended orotherwise combined with normal wool, i.e., wool which has not beenchemically modified to alter its dyestuff affinity, prior to dyeing,using conventional techniques. For example, the two types of wools canbe in the form of separate ends of a plied yarn, or blended and spun asa mixture of fibers into yarn. Preferably, to achieve best effects, thenormal and treated wool each constitute at least 25 percent andpreferably at least 35 percent of the mixture. The mixture is then dyedin an aqueous dyebath containing a dyestuif containing at least 2sulfonic acid groups; and an amount greater than 0.5 percent, calculatedon the weight of the wool, insufficient to reserve the dyestulf, of awater-soluble condensation product of an aryl sulfonic acid and analdone, at an initial dyebath pH in the presence of the wool of lessthan 5.9. Preferably, the dyebath additionally contains a dyestuffcontaining a total of less than 2 sulfonic acid and reactive groups. Thepolysulfonic acid dyestuifs contain at least 2 sulfonic acid groups, butpreferably 3 or more, e.g., 4, 5 or 6 such groups. The term sulfonicacid group excludes those groups in which the sulfonic group is in theform of an inner salt with a basic group. These dyestuffs canadditionally contain reactive groups in the molecule. The dyestuffscontaining reactive groups, e.g., vinyl sulfone or cyanuric chloridegroups, are referred to in the dyeing art as reactive dyestuffs.Desirably, the sum of the sulfonic acid groups and reactive groups is atleast 3 or 4. Included in the dyestutfscontaining 2 or more sulfonicacid groups are those referred to in the dyeing art as acid dyestuffs,milling dyestuffs, direct dyestuffs, cotton dyestuffs and cottonreactive dyestuffs. These dyestuffs are ordinarily supplied commerciallyin the form of their sodium salts.

The condensation products employed to achieve multicolor dyeings aregenerally known as retarding or leveling agents. They are characterizedchemically as condensation products of aryl, usually carbocyclic,sulfonic acids and an aldone. The term aldone as used herein means analdehydic or ketonic carbonyl compound, e.g., formaldehyde,acetaldehyde, benzaldehyde, benzoin, acetone, etc. These are awell-known and commonly employed class of compounds in the dyeing art.They each possess a sulfonic acid substituted aryl group in the moleculeand at least 1 additional acidic group, e.g., phenolic, carboxylic orsulfonic. Compounds within this definition are mono, di, or trisulfonicacid substituted benzene or naphthalenes which can further besubstituted with lower-alkyl, hydroxy, nitro, amino, etc., groups andwhich have been condensed with an aldone as described above to produce adimer, trimer or polymer linked by the aldone by a reaction well knownin the art. Compounds such as dihydroxy-diphenyl sulfone can also beincorporated in the condensation reaction to produce a mixedcondensation product. See US. 2,623,806. These compounds include thecondensation products of naphthalene-1 or naphthalene-2 sulfonic acid,or naphthalene- 2,7-disulfonic acid and formaldehyde and thealkali-metal salts thereof. Others include the condensation product ofphenol or cresol sulfonic acid and formaldehyde and the correspondingalkali-metal salts thereof. Still others include the condensationproducts of phenol, cresol, or naphthalene sulfonic acid and benzoin oracetone and their alkali-metal salts. These condensation productspreferably are also included in the solid shade dyeings describedherein.

Specific examples of such condensation products aredinaphthymethanedisulfonic acid, diphenylmethanedisulfonic acid,dihydroxyphenylmethanedisulfonic acid, dicresylmethanedisulfonic acid,dihydroxynaphthylmethanedisulfonic acid,dinitronaphthylmethanedisulfonic acid, dichloronaphthylmethanedisulfonicacid, diaminonaphthylmethanedisulfonic acid,dinaphthylmethane-2,7,2',7'-tetrasulfonic acid and the sodium salts ofeach.

The amount of aryl sulfonic acid-aldone condensation product employed inthe dyebath is at least 0.5 percent, calculated on the weight of theWool, but less than the amount which will reserve the dyestutf employed.An amount between about 1 percent and 5 percent is the usual range.

As in conventional acid dyeings, the dyebath will contain an organic orinorganic acid conventionally used in the dyeing art, e.g., acetic acid,formic acid, hydrochloric acid, sulfuric acid, phosphoric acid, lacticacid, citric acid or other strong acid which will provide an initial pHto the dyebath in the presence of the wool of less than 5, e.g., betweenabout 2.8 and 4.9, preferably below about 4.5. If desired, the pH can bevaried during the dyeing by employing ammonium sulfate or phosphate andthen permit the pH to drift lower during dyeing. The amount of acid tobe employed will depend upon the afiinity of the dyestuif or dyestuffsemployed in the dyeing to the wool in the presence of the condensationproduct as defined herein. Also, to enhance exhaustion of the dyestuif,additional amounts of acid can be added during the dyeing, according totechniques well known in the art.

The usual dyestufi additives, e.g., Glaubers salt or other materialsused as leveling agents or nonionic wetting agents, may be added to thedyebath to facilitate the dyeing process. However, as with otherdyeings, such additives may alter somewhat the results obtained. Forexample, cationics should be avoided and it is preferred to keep theseother additives to a minimum.

A striking effect can be obtained when the dyebath contains both apolysulfonic acid dyestufl' and one containing less than 2 sulfonic acidand reactive groups, particularly if an amount of the polysulfonic aciddyestulf is used which will be readily absorbed by the alkaline earthhydroxide treated portion of the wool yarn, and if an amount of anotherdyestuif of a distinctly different color and containing less than 2sulfonic acid and reactive groups is employed which will be readilyabsorbed by the normal wool.

If desired, the combined wools can, prior to dyeing, be given apretreatment with acid and formaldehyde or paraformaldehyde or with asulfonic acid condensation product as described herein in the presenceor absence of acetic, formic, hydrochloric or like acid and/orformaldehyde or paraformaldehyde, to enhance the subsequent dyeingeffect obtained.

For a further description of the techniques which ought to be employed,see US. 2,999,731 and British 680,862.

The following is illustrative of the process of this invention and isnot to be construed as limiting.

EXAMPLE I (a) To a 0.3 percent aqueous dispersion of calcium hydroxideheated to 140 F. add an amount of New Zealand 44s-50s carpet qualitywool fibers which will provide a liquor to wool ratio of at least 10:1and preferably at least 20:1, e.g., :1 or greater. The solutiondesirably contains a wetting agent, e.g., Mercerol G.V., Tergitol NPX,nonionic wetting agents. Maintain the wool in the solution for about 2to 10 minutes at the selected temperature while providing sufiicientagitation of the Wool and/or aqueous solution to ensure a uniformtreatment. Remove the wool after the selected time of reaction andimmediately wash the wool thoroughly, including an acid scour. Dry thewool in the conventional manner. Microscopic examination of the fiberscan be used to determine the maximum reaction time which may be used,along with tensile and elongation tests.

(b) The increased afiinity of the treated wool for hydrophilic dyestuffscan be demonstrated by dyeing the thus treated wool in fiber form in thepresence of comparable normal wool.

(c) Dye the above treated wool in the presence of an equal weight ofnormal Wool fibers at 200 F. for thirty minutes using 2 percent formicacid, 2 percent Synwool S.N., a formaldehyde-naphthalene sulfonic acidcondensation product, and 0.5 percent Procian Black HG, a cottonreactive dyestulf containing at least 2 sulfonic acid groups, followedby boiling for 15 minutes in the presence of an additional 1 percenteach of Synwool SN. and formic acid, all amounts calculated on theweight of the wool. In

each instance, the pretreated wool fibers are dyed substantially darkerthan the untreated wool fibers.

EXAMPLE II (a) Follow the procedure of Example I, treating 20 lb. toppre-scoured with a non-ionic detergent and rinsed, in a top dyeingmachine with a 0.3 percent dispersion of aqueous calcium hydroxide(standard U.S. Grade Gypsum) at a 30:1 liquor ratio at 137 F. withcirculating liquor for 7 minutes. Rinse several times with 140 F. Waterfollowed by an acetic acid rinse to bring the pH of the top to 5.5.

The thus treated wool can readily be dyed to exhaustion below the boilwith dyestuffs which with normal Wool do not exhaust or require longdyeings at the boil or above excessively damaging to the fiber. Thefollowing dyeing illustrates this ability.

(b) To the above described acetic acid liquor and top at pH 5.5 wasadded, calculated on the top, 0.5 percent each Tannasol Ddimethylnaphthyl disulfonic acid and Cibalan Black B.G.L., apremetallized dye containing less than 2 sulfonic acid groups. Thetemperature of the circulating liquor was raised to F. for 20 minutesand 7 then to 160 F. for an additional 30 minutes. The dyeing Wascomplete and comparable in light fastness, etc., to conventional ones atthe boil.

The following illustrate methods for obtaining color and white andmulticolor effects.

(c) In a dyebath with about a 20:1 liquor ratio containing 1.3 percentCibacron Brown BR (a polysulfonic acid dyestuff), 0.5 percentAnthraquinone Blue SWF (a 1 .sulfonic acid dycstuff), 2 percent Tamol SN(a naphthalene sulfonic acid-formaldehyde condensation product) and 2percent of acetic acid, calculated on the weight of the wool, thedyebath having an initial pH of about 4 in the presence of the wool, dyewool singles yarn of about 62-64s quality consisting of a blend of about50 percent normal wool fibers and 50 percent of wool fibers treatedaccording to the procedure of Example II(a) before blending with thenormal wool. Bring the solution to the boil in 45 minutes and dye at theboil for one hour or until exhaustion. A sharply contrasting bright blueand orange-brown stock dyed effect is obtained with the alkalinepretreated wool fibers being dyed blue with flecks of brown and thenormal wool fibers being dyed orangebrown with an undertone of lightblue.

If the yarn is in the form of a 2-ply yarn with one end consistingentirely of the wool fibers treated according to the procedure ofExample II and the other end consisting entirely of normal wool fibers,a novelty effect is obtained with a predominantly blue end spiralingaround a predominantly orange-brown end.

The same stock dyed and novelty spiral effects are obtained when suchyarns are knitted or woven into fabric before dyeing.

If the arylsulfonic acid-formaldehyde condensation product is omittedfrom the above dyeings, a faint twotone effect is obtained which isdistinctly different from the highly contrasting effect obtained in thepresence of the condensation product.

((1) Substantially the same dyeing effect is obtained as in ExampleII(c) using as the pretreated wool portion, fibers treated in the mannerdescribed in Example II(a) with an aqueous solution containing 5 percentCaCl 5 percent Na CO and 2 percent Na s at 140 F. for 5 minutes.

(e) Follow the procedure of Example II(d) using carpet woven from 2-plyyarn, one end of which consists of normal 44-48s New Zealand carpetquality wool and one of which consists of 44-48s New Zealand wool whichhas been treated for 5 minutes at 140 F. at pH 12 according to theprocedure of Example II(a). Dye in a carpet piece dyeing machine withconstant rotation of the carpet in open width form through the liquor.Bring to the boil in 45 minutes and dye at the boil until substantialexhaustion of the dyestuif is achieved.

The carpet is dyed a brilliant two-color effect caused by the spiralingof the plies of the yarn, one color being a bright blue on the normalwool and the other an orangebrown with a bluish tone on the alkalinepretreated wool.

(f) Dye fabric knit from singles yarn, formed of a 50:50 mixture of 64squality normal wool and 64s quality wool treated with calcium hydroxideaccording to the procedure of Example II(a), in a dyebath containing thefollowing ingredients, the percentages being calculated on the weight ofthe wool:

Percent Pyrazol Red 7 BSW (a 6 sulfonic acid dyestuff) 1.35Anthraquinone Blue SWF (a one sulfonic acid dyestuif) 0.25

The initial dyebath pH is below 4. Dye in the manner described above. Astriking burgundy mixed with reddish blue stock dyed effect is obtained.If the yarn is 2 ply with one end normal and the other endalkaline-pretreated W001, the normal wool end is dyed a bright bluetinged with red and the pretreated wool end is dyed a burgundy.

If the T amol SN is omitted a substantially solid reddish purple shadeis obtained.

EXAMPLE III Follow the procedure of Example I using a 1 percentdispersion of calcium hydroxide in water, with the solution brought to apH above 11, if desired, with some sodium hydroxide. At pH 11, heat toabout F. for about 5 minutes or less for the fine grade wools and atabout F. for 5 minutes or less for lower grade qualities of wool. In theabsence of strong base, heat between 4 and 10 minutes.

Following the above procedure, using barium hydroxide at a concentrationbetween 0.1 and 1 percent. Similarly, magnesium hydroxide can be usedbut the optimum treating temperature is about 10 F. or more, higher thanfor calcium and barium hydroxide.

EXAMPLE IV (a) Follow the procedure of Example III, solubilizing thecalcium hydroxide with sufficient sucrose to provide a 10 percentsolution, heating at 140 F. for 5 minutes at a pH of about 11.Substantially the same results are obtained when the wool is heated fromabout 2 to 15 minutes, but damage begins to occur at longer heatingtimes.

(b) Form a 2 ply yarn of 64s quality normal wool blended in about a50:50 mixture with 64s quality wool treated with calcium hydroxide inthe above-described manner.

Dye the yarn in a dyebath at about a 20:1 liquor ratio containing thefollowing ingredients, the percentages being calculated on the weight ofthe wool:

Percent Procian Orange G (a polysulfonic acid dyestuif) 0.14Anthraquinone Blue SWF (a one sulfonic acid dyestuff) 0.2 Phosphoricacid 3 Tamol SN (a naphthalene sulfonic acid-formaldehyde condensationproduct) l Paraformaldehyde l The dyebath has an initial pH below 4 inthe presence of the wool. Bring to the boil in about 45 minutes and dyeat the boil to dyestuff exhaustion. A stock dyed effect of a brightlight blue mixed with a bluish orange is obtained. If the yarn consistsof one end of normal wool and one end of alkaline-pretreated wool, aspiral effect is obtained with the normal wool end being dyed a lightblue and the pretreated wool end being an orange with a bluish tint.

If the Tamol SN is omitted, an overall blue effect tinged with orange isobtained in the case of the blended yarn and a slight two-tone effect isobtained in the case of normal wool end plied with the alkalinepretreated wool end.

(c) Follow the procedure of Example II(e), dyeing woven carpet formed ofthe 2-ply yarn prepared as described in Example IV(b) in a dyebathcontaining the following ingredients, the percentages being calculatedon the weight of the wool:

Percent Cibacron Brilliant Blue BR (a polysulfonic acid reactivedyestuff) 1.35 Xylene Yellow 2GP (l-sulfonic acid dyestuff) 0.3

Tannasol D (the acid form of a naphthalene sulfonic acid formaldehydecondensation product) Acetic acid The initial dyebath pH is less than4.5 in the presence of the wool. Dye in the manner described in ExampleII(e). The normal wool end of the yarn is dyed a greenish yellow and thealkaline pretreated wool end is dyed a bright blue, producing a striking2-color elfect on the carpet.

9 (d) Follow the procedure of Example IV(b) using a dyebath containingPercent dyestnff) 0.5 2

Procian Black HG a polysulfonic acid Tamol SN (a naphthalene sulfonicacid) Formic acid 2 The dyed yarn has a stock dyed blue-gray and whiteeffect. The white eifect can be enhanced by adding wool brighteners,preferably those containing less than 2- sulfonic acid groups, or otherdyestuffs or materials with little tintoral properties which have agreater aflinity for the normal wool than the calcium hydroxidepretreated wool.

EXAMPLE V To a carpet woven of 44-48s quality normal wool apply asolution of 1 percent Ca(OH) 10 percent sucrose and 2 percent Keltexsodium alginate by a rotating circular nylon brush which picks up thesolution and then presses against a bar so as to splatter the solutiononto the face of the carpet, thereby covering about one-thirdone-fifthof the surface of the carpet. Steam the carpet at 212 F. for ten minutesor less, wash thoroughly, including an acid scour.

When the thus-treated carpet is dyed in a dyebath described in Example11(f) or Example IV (b), (c) or (d), speckled color and white and2-col0r effects are obtained.

EXAMPLE VI (a) Agitate knitted fabric in a 0.3 percent aqueousdispersion of double hydrated calcium hydroxide at about a 30:1 liquorratio for 6 minutes at 136 F. Rinse thoroughly at that temperature andthen with cold water and finally with acetic acid until a liquor at pH5.5 was obtained.

Alternatively, the dry fabric can be wet out with a 0.3 to 1 percentcalcium chloride solution containing a nonionic wetting agent, thetemperature brought to 135- 140" F. and the pH gradually brought to10.5-11.5 with NaOH while rapidly agitating the fabric and treatmentbath, with a treatment time at that pH of 5 to 8 minutes.

(b) To the acetic acid liquor add 1 percent calculated on the wool,Cibalan Black BGL, a premetallized chromium containing dyestuff. Bringthe temperature to 160 F. for 30 minutes while agitating the liquor andfabric, thereby exhausting the liquor.

EXAMPLE VII (a) Treat worsted cloth of 56s quality with a 0.3 percentaqueous dispersion of double hydrated calcium hydroxide at a 30:1 liquorratio for 6 minutes at 138 F. Rinse several times with 140 F. water andthen 3 times with cold water. Add sufficient acetic acid to bring the pHto 5.5.

(b) To the cloth thus treated in water at a 20:1 liquor ratio, add 8times the weight of the cloth of 0.5 percent acetic acid and, calculatedon the weight of 10 cloth, 0.5 percent Tannasol D and 1 percent ProcianBlack HNS (ICI), a reactive dyestuff. Bring the temperature to 160 F.and dye at that temperature for minutes while circulating the liquor.Exhaustion is good and the resulting gray-white fleck effect dyeing hasa 5-6 light fastness.

What is claimed is:

1. A process for enhancing the dyestulf receptivity of wool whichcomprises the steps of (a) heating the wool in an aqueous bathcontaining a uniform 0.1 to 2 percent dispersion of an alkaline earthhydroxide at a pH from 9.5 to 13 at a temperature from to F. for aperiod of time less than 15 minutes which is non-damaging to the wool atthe selected pH and temperature in the absence of the alkaline earthhydroxide, thereby enhancing dyeability of the wool fiber whileretaining the scale structure of the wool in a substantially undamagedcondition and maintaining original tensile and elongation;

(b) thoroughly washing the wool; and

(c) bringing the wool to an acid pH.

2. A process according to claim 1 wherein the alkaline earth hydroxideis calcium hydroxide employed at a concentration of from 0.2 to onepercent, the pH is about that provided by the calcium hydroxide, and thewool is treated for from 2 to 10 minutes.

3. A method according to claim 1 wherein the alkaline earth hydroxide iscalcium hydroxide.

4. A process according to claim 3 wherein the pH is about that providedby the calcium hydroxide.

5. A method according to claim 1 wherein the wood is in the form of top.

References Cited UNITED STATES PATENTS 2,817,575 12/1957 Binder et a1854 2,999,731 9/1961 Harding 854 3,352,624 11/1967 Harding et a1. 8128OTHER REFERENCES Alexander: Wool, Its Chemistry and Physics, pp.174-180, pub. 1954 by Reinhold Pub. Corp., New York, NY.

Bowes: Progress in Leather Science 1920-1945, pp. 158-164, 188-189 and194.

Moncrief: Wool Shrinkage and Its Prevention, pp. 186-187, pub. 1953 -byNational Trade Press Inc., London.

Schmidt: Teintex, 1939, pp. 563-566.

Townend: J. Soc. Dyers and Col., pub. 1945, pp. 144- 150.

DONALD LEVY, Primary Examiner.

US. Cl. X.R. 8-54

